efi_loader: Reserve unaccessible memory
PATCH v2 1/1 efi_loader: Reserve unaccessible memory
On some systems, not all RAM may be usable within U-Boot. Maybe the memory maps are incomplete, maybe it's used as workaround for broken DMA. But whatever the reason may be, a platform can say that it does not wish to have its RAM accessed above a certain address by defining board_get_usable_ram_top().
In the efi_loader world, we ignored that hint, mostly because very few boards actually have real restrictions around this.
So let's honor the board's wish to not access high addresses during boot time. The best way to do so is by indicating the respective pages as "allocated by firmware". That way, Operating Systems will still use the pages after boot, but before boot no allocation will use them.
---
v1 -> v2:
- Reserve banks that start above ram_top
- Improve inline comments
- Fix 32bit target with ram_top = 0 (>=4G)
--- include/common.h | 11 +++++++++++ lib/efi_loader/efi_memory.c | 32 +++++++++++++++++++++++++++++--- 2 files changed, 40 insertions(+), 3 deletions(-)
include/common.h +11 -0
@@ -106,6 +106,17 @@ int mdm_init(void);void board_show_dram (phys_size_t size);/** +* Get the uppermost pointer that is valid to access +* +* Some systems may not map all of their address space. This function allows +* boards to indicate what their highest support pointer value is for DRAM +* access. +* +* @param total_size Size of U-Boot (unused?) +*/ +ulong board_get_usable_ram_top (ulong total_size); + +/** * arch_fixup_fdt() - Write arch-specific information to fdt * * Defined in arch/$(ARCH)/lib/bootm-fdt.c
lib/efi_loader/efi_memory.c +29 -3
@@ -551,8 +551,13 @@ efi_status_t efi_get_memory_map(efi_uintn_t *memory_map_size,__weak void efi_add_known_memory (void ) { +u64 ram_top =board_get_usable_ram_top (0 ) & ~EFI_PAGE_MASK ;int i; +/* Fix for 32bit targets with ram_top at 4G */ +if (!ram_top) + ram_top =U32_MAX ; +/* Add RAM */ for (i =0 ; i <CONFIG_NR_DRAM_BANKS ; i++) {u64 ram_end, ram_start, pages;
@@ -564,11 +569,32 @@ __weak void efi_add_known_memory(void) ram_end &= ~EFI_PAGE_MASK ; ram_start = (ram_start +EFI_PAGE_MASK ) & ~EFI_PAGE_MASK ; -if (ram_end > ram_start) { - pages = (ram_end - ram_start) >>EFI_PAGE_SHIFT ; +if (ram_end <= ram_start) { +/* Invalid mapping, keep going. */ +continue ; + } + + pages = (ram_end - ram_start) >>EFI_PAGE_SHIFT ; +efi_add_memory_map (ram_start, pages, +EFI_CONVENTIONAL_MEMORY , false); + +/* +* Boards may indicate to the U-Boot memory core that they +* can not support memory above ram_top. Let's honor this +* in the efi_loader subsystem too by declaring any memory +* above ram_top as "already occupied by firmware". +*/ +if (ram_top < ram_start) { +/* ram_top is before this region, reserve all */ efi_add_memory_map (ram_start, pages, -EFI_CONVENTIONAL_MEMORY , false); +EFI_BOOT_SERVICES_DATA , true); + }else if ((ram_top >= ram_start) && (ram_top < ram_end)) { +/* ram_top is inside this region, reserve parts */ + pages = (ram_end - ram_top) >>EFI_PAGE_SHIFT ; + +efi_add_memory_map (ram_top, pages, +EFI_BOOT_SERVICES_DATA , true); } } }
Signature · 1 line
2.12.3
PATCH v2 1/1 efi_loader: Reserve unaccessible memory
Quoted 15 lines · Alexander Graf
On some systems, not all RAM may be usable within U-Boot. Maybe the memory maps are incomplete, maybe it's used as workaround for broken DMA. But whatever the reason may be, a platform can say that it does not wish to have its RAM accessed above a certain address by defining
board_get_usable_ram_top().In the
efi_loaderworld, we ignored that hint, mostly because very few boards actually have real restrictions around this.So let's honor the board's wish to not access high addresses during boot time. The best way to do so is by indicating the respective pages as "allocated by firmware". That way, Operating Systems will still use the pages after boot, but before boot no allocation will use them.
lib/efi_loader/efi_memory.c efi_status_t efi_get_memory_map(efi_uintn_t *memory_map_size, · line 559
Quoted 9 lines
lib/efi_loader/efi_memory.c +4
-0__weak void efi_add_known_memory (void ) { +u64 ram_top =board_get_usable_ram_top (0 ) & ~EFI_PAGE_MASK ;int i; +/* Fix for 32bit targets with ram_top at 4G */ +if (!ram_top) + ram_top =U32_MAX ;
Don't you need to &= ~EFI_PAGE_MASK after the U32_MAX assignment too? Perhaps just do that once:
u64 ram_top = board_get_usable_ram_top(0); /* Fix for 32bit targets with ram_top at 4G */ if (!ram_top) ram_top = U32_MAX; ram_top &= & ~EFI_PAGE_MASK;
Otherwise,
PATCH v2 1/1 efi_loader: Reserve unaccessible memory
In reply to Alexander GrafQuoted 56 lines · Alexander Graf
On some systems, not all RAM may be usable within U-Boot. Maybe the memory maps are incomplete, maybe it's used as workaround for broken DMA. But whatever the reason may be, a platform can say that it does not wish to have its RAM accessed above a certain address by defining
board_get_usable_ram_top().In the
efi_loaderworld, we ignored that hint, mostly because very few boards actually have real restrictions around this.So let's honor the board's wish to not access high addresses during boot time. The best way to do so is by indicating the respective pages as "allocated by firmware". That way, Operating Systems will still use the pages after boot, but before boot no allocation will use them.
Reported-by Baruch Siach <[email protected]>Signed-off-by Alexander Graf <[email protected]>---
v1 -> v2:
- Reserve banks that start above
ram_top
- Improve inline comments
- Fix 32bit target withram_top= 0 (>=4G)--- include/common.h | 11 +++++++++++ lib/efi_loader/efi_memory.c | 32 +++++++++++++++++++++++++++++--- 2 files changed, 40 insertions(+), 3 deletions(-)include/common.h +11
-0@@ -106,6 +106,17 @@ int mdm_init(void);void board_show_dram (phys_size_t size);/** +* Get the uppermost pointer that is valid to access +* +* Some systems may not map all of their address space. This function allows +* boards to indicate what their highest support pointer value is for DRAM +* access. +* +* @param total_size Size of U-Boot (unused?) +*/ +ulong board_get_usable_ram_top (ulong total_size); + +/** * arch_fixup_fdt() - Write arch-specific information to fdt * * Defined in arch/$(ARCH)/lib/bootm-fdt.c lib/efi_loader/efi_memory.c +0
-0
lib/efi_loader/efi_memory.c efi_status_t efi_get_memory_map(efi_uintn_t *memory_map_size, · line 559
Quoted 9 lines
lib/efi_loader/efi_memory.c +4
-0@@ -551,8 +551,13 @@ efi_status_t efi_get_memory_map(efi_uintn_t *memory_map_size,__weak void efi_add_known_memory (void ) { +u64 ram_top =board_get_usable_ram_top (0 ) & ~EFI_PAGE_MASK ;int i; +/* Fix for 32bit targets with ram_top at 4G */ +if (!ram_top) + ram_top =U32_MAX ;
Why don't you set ram_top to (1 << 32)? ram_top is u64 anyway. We do not want something ending with 0xfff to be passed to efi_add_memory_map.
Are we sure there will never be 64bit machines with a memory bank ending at 1 << 64? What would be the value of ram_end and ram_top in such a case?
Regards
Heinrich
Quoted 41 lines
lib/efi_loader/efi_memory.c +25
-3+/* Add RAM */ for (i =0 ; i <CONFIG_NR_DRAM_BANKS ; i++) {u64 ram_end, ram_start, pages;@@ -564,11 +569,32 @@ __weak void efi_add_known_memory(void) ram_end &= ~EFI_PAGE_MASK ; ram_start = (ram_start +EFI_PAGE_MASK ) & ~EFI_PAGE_MASK ; -if (ram_end > ram_start) { - pages = (ram_end - ram_start) >>EFI_PAGE_SHIFT ; +if (ram_end <= ram_start) { +/* Invalid mapping, keep going. */ +continue ; + } + + pages = (ram_end - ram_start) >>EFI_PAGE_SHIFT ; +efi_add_memory_map (ram_start, pages, +EFI_CONVENTIONAL_MEMORY , false); + +/* +* Boards may indicate to the U-Boot memory core that they +* can not support memory above ram_top. Let's honor this +* in the efi_loader subsystem too by declaring any memory +* above ram_top as "already occupied by firmware". +*/ +if (ram_top < ram_start) { +/* ram_top is before this region, reserve all */ efi_add_memory_map (ram_start, pages, -EFI_CONVENTIONAL_MEMORY , false); +EFI_BOOT_SERVICES_DATA , true); + }else if ((ram_top >= ram_start) && (ram_top < ram_end)) { +/* ram_top is inside this region, reserve parts */ + pages = (ram_end - ram_top) >>EFI_PAGE_SHIFT ; + +efi_add_memory_map (ram_top, pages, +EFI_BOOT_SERVICES_DATA , true); } } }
PATCH v2 1/1 efi_loader: Reserve unaccessible memory
Quoted 63 lines · Heinrich Schuchardt
Quoted 62 lines · Alexander Graf
On some systems, not all RAM may be usable within U-Boot. Maybe the memory maps are incomplete, maybe it's used as workaround for broken DMA. But whatever the reason may be, a platform can say that it does not wish to have its RAM accessed above a certain address by defining
board_get_usable_ram_top().In the
efi_loaderworld, we ignored that hint, mostly because very few boards actually have real restrictions around this.So let's honor the board's wish to not access high addresses during boot time. The best way to do so is by indicating the respective pages as "allocated by firmware". That way, Operating Systems will still use the pages after boot, but before boot no allocation will use them.
Reported-by Baruch Siach <[email protected]>Signed-off-by Alexander Graf <[email protected]>---
v1 -> v2:
- Reserve banks that start above
ram_top
- Improve inline comments
- Fix 32bit target withram_top= 0 (>=4G)--- include/common.h | 11 +++++++++++ lib/efi_loader/efi_memory.c | 32 +++++++++++++++++++++++++++++--- 2 files changed, 40 insertions(+), 3 deletions(-)include/common.h +11
-0@@ -106,6 +106,17 @@ int mdm_init(void);void board_show_dram (phys_size_t size);/** +* Get the uppermost pointer that is valid to access +* +* Some systems may not map all of their address space. This function allows +* boards to indicate what their highest support pointer value is for DRAM +* access. +* +* @param total_size Size of U-Boot (unused?) +*/ +ulong board_get_usable_ram_top (ulong total_size); + +/** * arch_fixup_fdt() - Write arch-specific information to fdt * * Defined in arch/$(ARCH)/lib/bootm-fdt.c lib/efi_loader/efi_memory.c +1
-0@@ -551,8 +551,13 @@ efi_status_t efi_get_memory_map(efi_uintn_t *memory_map_size,__weak void efi_add_known_memory (void ) { +u64 ram_top =board_get_usable_ram_top (0 ) & ~EFI_PAGE_MASK ;int i;
Quoted 6 lines
lib/efi_loader/efi_memory.c efi_status_t efi_get_memory_map(efi_uintn_t *memory_map_size, · line 559
Quoted 3 lines
lib/efi_loader/efi_memory.c +3
-0+/* Fix for 32bit targets with ram_top at 4G */ +if (!ram_top) + ram_top =U32_MAX ;Why don't you set
ram_topto (1 << 32)?ram_topis u64 anyway. We do not want something ending with0xfffto be passed toefi_add_memory_map.
Ugh, yes. Of course. And obviously that's 0x100000000ULL to make sure it works fine on 32bit :).
Quoted 2 lines
Are we sure there will never be 64bit machines with a memory bank ending at 1 << 64? What would be the value of
ram_endandram_topin such a case?
I think we can be pretty sure of that, yes :). No machine today even comes close to that many physical address bits supported.
Alex